Data Sources:
(Source1): Traffic bandwidth in bytes passing through each of the
backbone nodes was provided by Merit Network, Inc., NCAR, and NASA JPL.
During December 1994, total inbound traffic on the backbone was 18.5 trillion bytes.

Data Aggregation:
(Aggregate1): Networks that exist in the same city and report
to the same backbone node are aggregated into a single
colored line. During December 1994, (for byte traffic into the
ANS/NSFNET T3 backbone from its
client networks), 24,435 domestic client
networks were aggregated into 12,177 virtual traffic connections.

Data Filters:
(Filter1): Intermediate connections are removed so that only a
hypothetical direct connection between each node of the backbone and all of
its clients is displayed.